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Cymbidium (sim-bid-ee-um) must rank as one of the best known and widely popular of all orchids. The genus consists of about 50 species and, from these; thousands of hybrids have been bred. The wild types are found growing naturally in China, Japan, through the Himalayas, South East Asia to Australia.
Conservatories or cool greenhouses suit these plants where a minimum winter night temperature of between 8-12°C can be maintained. They can also be grown in the home but to initiate flower shoots they must have cool nights throughout the spring and summer months. If you have a garden or patio we advise that you stand the plants outside towards the end of May until the middle of September when the night temperatures start to drop. Never leave outside when frosty.
Fairly strong light is good for these plants. If they are grown in a conservatory or greenhouse then 50%-60% shading is needed during the summer months to prevent leaf burn and overheating. If you are growing them outside in the summer, early morning sun is ideal but do provide some shade against the strongest sunlight
Good air movement is essential for Cymbidium growth. Ventilate the greenhouse whenever the weather permits. Overheating in the summer is very bad for the plants.
WATERING & FERTILISING
Never allow the plants to dry out and always keep the compost moist. Normally, watering once a week is sufficient but during the hot summer months it may be necessary to water twice weekly. Stand the plant in a bucket of water for just 30 minutes.
Use a well balanced orchid fertilizer at the recommended strength throughout the spring and summer. Reduce the strength to half the recommended dose through autumn and winter.
Keep these orchids cool and light in the winter and outdoors in the summer to help re-flowering. Keeping them too warm at night can prevent blooming.
This is a common problem in the winter as the lack of light often causes the buds to drop off. To get the flowers to open properly keep the plant in a cool, light position until all the blooms have opened, then by all means move them to somewhere else where you can enjoy them. If the plant is moved from a cool, light place to a warm, shady room whilst in bud, the shock of the change in conditions can cause them to drop prematurely.
POTTING & DIVIDING
The best time to repot and divide cymbidiums is between the end of February and the end of April. Never overpot. Only repot into pots where there is just enough room for the following year’s growth. If they need dividing, using a sterile knife, cut the plant at the rhizome to give divisions of not less than three bulbs. Use a bark based orchid compost which is moist.
Culture information taken from the Growers and Buyers Guide to Orchids in the UK – 2013 (Golden Guide).
Photographs supplied by S. Pask unless stated.